(Reuters) - Under an unusual arrangement, Paul Manafort's attorney has kept Donald Trump informed about the former campaign chairman's meetings with prosecutors investigating Russian meddling in the 2016 U.S. election and, according to Trump's lawyer, Manafort has not said anything damaging about the president.

Rudy Giuliani, who represents Trump in the Russia probe, told Reuters that he had spoken with Manafort's lawyer, Kevin Downing, as recently as last week. Manafort pleaded guilty on Sept. 14 to violating foreign lobbying laws and trying to obstruct justice. He was convicted at trial in another case in August.

Giuliani said the conversations were occurring under a so-called joint defence agreement, which allows lawyers who represent different clients to exchange information without violating attorney-client privilege.

Legal experts said it was unusual for such an agreement to remain in effect after a person pleads guilty and agrees to cooperate with prosecutors as Manafort has done.

Manafort is talking to Special Counsel Robert Mueller "about a lot of things, none of which are incriminating with regard to the president," Giuliani said in one of several conversations with Reuters this month.

Giuliani said he was told by Downing that Manafort had met with Mueller's team roughly a half dozen times.

Downing did not respond to requests for comment.

Giuliani's account of his communications with Downing comes at what may be a critical point in Mueller's investigation of election meddling and any possible coordination between Russia and the Trump campaign, which the president denies.

Mueller has started drafting a report outlining his findings that will be submitted to Deputy Attorney General Rod Rosenstein, who oversees Mueller's team, and could ultimately be made public, a person familiar with the matter said.

Peter Carr, a spokesman for Mueller, declined to comment.

New York lawyer Harry Sandick, a former federal prosecutor, said that there are some cases in which a joint defence agreement can survive a cooperation agreement, such as if Manafort is providing information about people other than Trump.

"In general, you can only have a joint defence agreement where there is a common interest between two people in defeating a prosecution," Sandick said.

He said lawyers can have unprivileged conversations with their clients' approval.

Giuliani said his conversations with Downing had been limited to areas that affect Trump.

"If he wants to communicate information, Manafort, he's allowed to do that. There's nothing that stops him from doing that," Giuliani said. "All I'm interested in is: Is there anything we need to know with regard to us?"

Giuliani said Downing had not shared specific facts with him regarding Manafort's discussions with prosecutors.

"He's just telling me the conclusion that he's not in a conflicted position with us," said Giuliani, who has been very public in his defence of Trump, appearing regularly on TV disputing aspects of the investigation and calling it a political witch hunt just as the president has.

Moscow rejects the conclusions of U.S. intelligence agencies that state-supported operatives interfered in the election.

Legal experts said Manafort's lawyer may be trying to remain on good terms with the Trump camp in the hopes that Manafort will ultimately receive a presidential pardon.

"Maybe he is thinking he can sort of have it both ways -cooperate and draw less ire from Mueller and hopefully still get a pardon from Trump," said Renato Mariotti, a former federal prosecutor.

Giuliani said he did not know why Manafort's lawyer is sharing information with him.

Manafort, who made tens of millions of dollars working for pro-Kremlin politicians in Ukraine, was among Trump campaign aides who attended a June 2016 meeting at Trump Tower with a group of Russians offering damaging information on Democratic candidate Hillary Clinton.